What action can you perform using the omnibus feature?

The omnibus feature primarily refers to the ability to search for multiple topics or perform comprehensive inquiries across various domains simultaneously. This functionality enhances user experience by allowing for a unified search that retrieves information from different sources, making it more efficient to find relevant data instead of executing separate searches for each topic.

In the context of the other options, sending emails directly pertains to using an email client or service, which does not leverage the organizational capabilities of the omnibus feature. Customizing web addresses typically involves setting up personal or branded URLs, a task that is unrelated to the search capabilities emphasized by the omnibus function. Scheduling events on a calendar involves calendar applications, which is focused on time management rather than the multifaceted search capabilities provided by an omnibus feature.